The APAF1 Knockout HT29 Polyclonal Cells are a CRISPR/Cas9-edited polyclonal knockout cell population targeting the APAF1 gene in human HT29 colorectal adenocarcinoma cells. This product provides a mixed population of cells with disrupted APAF1, enabling loss-of-function studies of the intrinsic apoptotic pathway. CRISPR/Cas9-mediated gene disruption ablates APAF1 expression without requiring clone selection, offering a flexible and rapid tool for functional genomics and drug discovery. Researchers can use these cells to investigate apoptosis regulation and screen for modulators of cell death mechanisms.
HT29 is a well-characterized human colorectal adenocarcinoma epithelial cell line, originating from a primary colon adenocarcinoma of a 44-year-old Caucasian female. It serves as a robust model for intestinal epithelial biology, colorectal cancer research, and drug transport studies. HT29 cells form polarized monolayers and retain key features of the intestinal epithelium, making them particularly useful for examining the molecular underpinnings of apoptosis resistance in colorectal cancers. Notably, HT29 cells harbor a mutant TP53 gene, providing a unique context to explore p53-independent apoptotic signaling.
APAF1 is a pro-apoptotic scaffold that forms the apoptosome upon binding mitochondrial cytochrome c. This complex recruits and activates caspase-9, which subsequently cleaves executioner caspases like caspase-3, leading to proteolytic cleavage of substrates such as PARP. Upstream, TP53 transcriptionally regulates APAF1, while the BCL-2 family members BAX and BAK promote cytochrome c release. APAF1 interacts with pro-caspase-9 and is inhibited by HSP70; APIP also modulates its function. Through these molecular interactions, APAF1 integrates death signals to drive cellular demolition, playing a pivotal role in the intrinsic apoptotic pathway.
In colorectal cancer, APAF1 loss is associated with apoptosis evasion, chemoresistance, and tumor progression. The APAF1 knockout in HT29 cells recapitulates this clinical phenotype, enabling the dissection of apoptosis-independent survival mechanisms. Given the mutant TP53 background of HT29, this model is ideal for studying p53-independent regulation of the intrinsic pathway. It facilitates the identification of synthetic lethal partners and the screening of pro-apoptotic agents that can bypass APAF1 deficiency, offering valuable insights into therapeutic strategies for APAF1-dysregulated cancers.
Researchers can employ these polyclonal knockout cells in a panel of downstream assays to probe apoptotic function. Western blotting can assess cleavage of caspase-9, caspase-3, and PARP; caspase-9 activity assays directly measure apoptosome function. Cytochrome c release assays and immunofluorescence for apoptosome formation provide spatial-temporal readouts. Cell viability assays (MTT, Annexin V/PI flow cytometry) and RT-qPCR for apoptotic genes further characterize the knockout phenotype. Typical applications include studying apoptosis mechanisms, screening pro-apoptotic compounds, and validating p53-mediated cell death pathways. For further information, contact Ascent Research.
