The ATM Knockout HT29 Polyclonal Cells comprise a CRISPR/Cas9-edited polyclonal knockout cell population derived from the human HT29 colorectal adenocarcinoma cell line. This loss-of-function model enables targeted disruption of the ATM gene, encoding the ATM serine/threonine kinase, a central mediator of the DNA damage response. The polyclonal nature of the population preserves heterogeneous knockout alleles without single-cell cloning, providing a versatile tool for studying ATM-dependent signaling in a genetically flexible background.
The HT29 parental cell line is a widely characterized epithelial model of human colorectal adenocarcinoma. These cells harbor mutations in the APC and TP53 tumor suppressor genes, and exhibit an epithelial morphology with the capacity for enterocytic differentiation under appropriate culture conditions. Extensively employed in intestinal biology and drug permeability investigations, HT29 cells offer a physiologically relevant context for colorectal cancer research and pharmacological assessments.
ATM functions as a sensor of DNA double-strand breaks, becoming activated through recruitment by the MRN complex comprising MRE11, RAD50, and NBS1. Upon activation, ATM auto-phosphorylates and subsequently phosphorylates a network of downstream effectors, including the checkpoint kinase CHK2, the tumor suppressor p53, histone variant H2AX (forming ??-H2AX), and BRCA1. These phosphorylation events coordinate cell cycle arrest, facilitate DNA repair through homologous recombination and non-homologous end joining, and trigger apoptosis when damage is irreparable. ATM also engages with interacting factors such as ATR, DNA-PKcs, Tip60 (KAT5), and the phosphatase PP2A, integrating signals from oxidative stress and replication stress to fine-tune cellular outcomes.
In the HT29 background, which already lacks functional p53 due to endogenous TP53 mutation, ATM knockout provides a unique system to dissect p53-independent roles of ATM in DNA repair and cell survival. This model is particularly valuable for colorectal cancer research, as it allows elucidation of how ATM deficiency influences genomic stability, tumor progression, and sensitivity to DNA-damaging therapeutics in an epithelial tumor context. The combination of ATM loss with mutant APC and TP53 mimics genetic alterations frequently observed in colorectal malignancies, enhancing the relevance for translational studies.
Researchers can utilize these polyclonal knockout cells to investigate DNA damage response mechanisms, assess drug sensitivity??particularly to PARP inhibitors and topoisomerase poisons like etoposide??and monitor ATM pathway activity using standard assays. Western blotting for phosphorylated substrates, immunofluorescence detection of ??-H2AX foci, flow cytometric cell cycle analysis, apoptosis quantification, and clonogenic survival assays after genotoxic stress are all applicable. This product also serves in drug sensitivity screens and DNA repair reporter assays, supporting efforts in cancer biology and therapeutic development. For additional technical details or ordering information, please contact Ascent Research.
