APEX1 Knockout TE1 Polyclonal Cells are a CRISPR/Cas9-edited polyclonal population derived from the TE1 human esophageal squamous cell carcinoma line, featuring targeted disruption of the APEX1 gene. This knockout model is generated without selection for a single clonal derivative, instead providing a polyclonal mixture of edited cells, which can be advantageous for studying heterogeneous biological responses. The product serves as a loss-of-function tool to investigate the multifaceted roles of APEX1, also known as APE1/Ref-1, in DNA repair and redox signaling within a cancer-relevant context.
The TE1 host cell line originates from a human esophageal squamous cell carcinoma and is widely used in esophageal cancer research. These adherent epithelial cells retain characteristics of the primary tumor, including oncogenic mutations and dysregulated signaling pathways, making them a suitable platform to examine gene function in esophageal squamous cell carcinogenesis. The parental TE1 line provides a defined genetic background against which the consequences of APEX1 ablation can be assessed, enabling rigorous comparison of DNA damage responses and cellular redox dynamics.
APEX1 encodes a dual-function enzyme that acts as the major apurinic/apyrimidinic endonuclease in the DNA base excision repair (BER) pathway and as a redox factor (Ref-1) that maintains transcription factors in a reduced, active state. In BER, APEX1 cleaves abasic sites generated by DNA glycosylases, processing the lesion for subsequent repair by DNA polymerase ??, XRCC1, and DNA ligase III. Concurrently, its redox activity regulates the DNA-binding activity of transcription factors such as p53, NF-??B, AP-1, and HIF-1?? by reducing critical cysteine residues. Upstream signals including reactive oxygen species (ROS) and DNA damage activate APEX1, while interacting partners like PCNA and XRCC1 coordinate its enzymatic functions. Through these mechanisms, APEX1 integrates genomic maintenance with transcriptional responses to oxidative stress.
Disruption of APEX1 in TE1 cells is predicted to impair BER capacity, leading to accumulation of apurinic/apyrimidinic sites and heightened genomic instability under oxidative stress, which may sensitize cells to DNA-damaging agents or alter proliferation. Additionally, loss of Ref-1 activity could compromise redox activation of key transcription factors, potentially dampening survival signaling and altering apoptosis thresholds. In the context of esophageal squamous cell carcinoma, where APEX1 is often overexpressed and associated with poor prognosis, this knockout model enables dissection of its contributions to tumor cell fitness, drug resistance, and oxidative stress adaptation.
Typical research applications include mechanistic studies of DNA base excision repair, oxidative stress signaling, and transcription factor redox regulation in cancer. This polyclonal model is compatible with a variety of downstream assays, such as Western blotting and RT-qPCR for gene expression analysis, comet assays and ??H2AX immunostaining for DNA damage quantification, Annexin V and MTT assays for apoptosis and viability, clonogenic survival assays, redox activity measurements, and high-throughput approaches like RNA-seq and ChIP-qPCR. For additional information, please contact Ascent Research.
