The APEX2 Knockout A-549 Polyclonal Cells are a CRISPR/Cas9-edited polyclonal knockout cell population derived from the A-549 human lung adenocarcinoma cell line. This loss-of-function model features targeted disruption of the APEX2 gene, which encodes apurinic/apyrimidinic endodeoxyribonuclease 2, a critical enzyme in the base excision repair (BER) pathway. The polyclonal format provides a cost-effective, heterogeneous pool of edited cells, enabling rapid functional studies of DNA repair without requiring single-cell cloning.
The A-549 parental line is a widely recognized model of human lung adenocarcinoma, initially established from the tumor tissue of a 58-year-old male. These adherent epithelial cells exhibit alveolar type II characteristics and are extensively employed in cancer biology, drug response profiling, and cellular stress research. The A-549 context is particularly relevant for investigating DNA damage responses in pulmonary adenocarcinoma, a setting where oxidative stress and genomic instability are key drivers of malignancy.
APEX2 functions as an apurinic/apyrimidinic endodeoxyribonuclease that cleaves abasic sites during BER, acting downstream of DNA glycosylases and under regulation by ATM and ATR checkpoint kinases in response to DNA damage. It interacts with proliferating cell nuclear antigen (PCNA), flap endonuclease 1 (FEN1), X-ray repair cross-complementing protein 1 (XRCC1), and DNA polymerase beta (Pol ??) to coordinate processing of repair intermediates. Disruption of APEX2 abrogates efficient abasic site cleavage, causing accumulation of unrepaired DNA lesions, compromised genomic stability, and increased sensitivity to genotoxic agents such as alkylating chemicals and reactive oxygen species.
In A-549 lung adenocarcinoma cells, the APEX2 knockout model amplifies the intrinsic genomic instability and altered DNA repair capacity of cancer cells. Loss of BER function through APEX2 deficiency creates a powerful system for exploring synthetic lethal interactions, as tumor cells become reliant on compensatory repair pathways. Combining this knockout with inhibitors of alternative DNA repair factors or with DNA-damaging chemotherapeutics reveals vulnerabilities that may be exploited therapeutically. The model also serves to dissect how BER dysfunction contributes to tumor progression and drug resistance in an epithelial cancer background.
Researchers can utilize these polyclonal knockout cells for mechanistic investigations of DNA repair, synthetic lethality screens, and chemosensitivity testing against methyl methanesulfonate or oxidative stress inducers. Representative assays include immunofluorescence detection of gamma-H2AX foci, alkaline comet assay for DNA strand breaks, clonogenic survival, and flow cytometric cell cycle analysis. Co-immunoprecipitation and Western blotting enable assessment of APEX2 interactions with PCNA, XRCC1, and Pol ??, while RT-qPCR confirms gene disruption. This model also supports broader studies of genomic instability and its contribution to lung adenocarcinoma pathogenesis. For additional details or custom configurations, please contact Ascent Research.
