The APOBEC3A Knockout CAL-27 Polyclonal Cells comprise a CRISPR/Cas9-edited polyclonal knockout cell population derived from the human tongue squamous cell carcinoma epithelial cell line CAL-27. This product provides a mixed population of cells with targeted disruption of the APOBEC3A gene, enabling loss-of-function studies in a head and neck cancer context. The polyclonal format ensures genetic heterogeneity that more closely mimics natural tumor variation compared to monoclonal derivatives, while maintaining knockout functionality across the bulk culture. Researchers can use this model to interrogate the roles of APOBEC3A without the confounding effects of clonal selection. The cells are suitable for a broad range of downstream analyses, provided proper single-cell clonal isolation is not a prerequisite.
CAL-27 is an established cell line derived from a tongue squamous cell carcinoma from a male patient and is widely recognized as a representative model for head and neck squamous cell carcinoma (HNSCC). Characterized by epithelial morphology, CAL-27 cells retain key features of the original tumor and are commonly employed in cancer biology investigations, including drug response profiling and oncogenic signaling studies. The cell line’s robust growth characteristics and well-documented genetic background make it an ideal host for CRISPR-based gene editing. In the context of APOBEC3A knockout, the CAL-27 background offers a clinically relevant platform for dissecting mutagenic processes and innate immune interactions in one of the most mutationally disordered cancer types.
APOBEC3A encodes a cytidine deaminase that catalyzes C-to-U editing in single-stranded DNA, contributing to both antiviral restriction and endogenous genomic instability. The enzyme is transcriptionally activated by type I interferons such as IFN-alpha and IFN-beta through a JAK-STAT pathway involving IFNAR, JAK1, TYK2, STAT1, STAT2, and the transcription factor complex IRF9. Additional upstream regulators include NF-kappaB and cytoplasmic nucleic acid sensors such as the cGAS-STING and RIG-I-like receptor pathways. APOBEC3A preferentially targets genomic hotspots, including TP53 and PIK3CA, and interacts with replication and repair factors such as RPA, PCNA, and UNG, as well as forming homodimers and heterodimers with APOBEC3B. Its activity induces DNA damage, marked by gamma-H2AX foci, and shapes tumor mutation landscapes through apolipoprotein B mRNA-editing enzyme catalytic polypeptide (APOBEC)-mediated mutagenesis.
Knockout of APOBEC3A in CAL-27 cells abrogates a major source of cytidine deamination-driven mutation, altering the DNA damage response and modifying interferon-associated innate immune gene expression. This model allows dissection of APOBEC-dependent mutagenesis from other mutational processes operative in HNSCC. Loss-of-function studies can clarify how APOBEC3A contributes to the acquisition of drug-resistant subclones, particularly in the context of cisplatin and other genotoxic therapies. By comparing polyclonal knockout populations to wild-type controls, researchers can measure changes in mutational signatures, interferon-stimulated gene (ISG) expression, and tumor cell fitness under selective pressures, providing insights into cancer evolution and therapeutic vulnerability.
Typical research applications include targeted DNA sequencing to define APOBEC mutation signatures, RT-qPCR profiling of ISGs such as ISG15, MX1, and OAS1, and immunofluorescence detection of DNA damage markers. The model supports functional validation of APOBEC3A in innate immune signaling by assessing responses to IFN-alpha stimulation or viral nucleic acid mimics. Moreover, it facilitates drug sensitivity assays, apoptosis and cell cycle analyses by flow cytometry, and biomarker discovery efforts. The APOBEC3A Knockout CAL-27 Polyclonal Cells provide a robust, disease-relevant platform for deciphering the interplay between antiviral immunity and genome integrity. For additional information, please contact Ascent Research.
