The CD274 Knockout AGS Polyclonal Cells represent a CRISPR/Cas9-edited polyclonal knockout cell population designed to disrupt the CD274 gene in the Homo sapiens AGS gastric adenocarcinoma cell line. This polyclonal population provides a heterogeneous loss-of-function model for studying PD-L1 biology, generated by targeted CRISPR/Cas9-mediated gene disruption without selection for a single clonal genotype. The absence of the PD-L1 checkpoint molecule enables detailed investigation of tumor-immune interactions and signaling pathways in a gastric cancer context.
The AGS host cell line, derived from a human gastric adenocarcinoma, is a well-established epithelial model widely used to dissect the molecular mechanisms of gastric carcinogenesis and tumor progression. These adherent cells exhibit characteristic features of gastric epithelium, making them suitable for evaluating oncogenic signaling and host-tumor microenvironment interactions. As a model of gastric adenocarcinoma, AGS cells are particularly relevant for examining pathways that drive immune evasion and therapeutic resistance in upper gastrointestinal malignancies.
CD274 encodes the immune checkpoint ligand PD-L1, which upon binding to the PD-1 receptor (PDCD1) on activated T cells, recruits the tyrosine phosphatase SHP-2 to the T cell receptor (TCR) signaling complex. SHP-2 dephosphorylates key proximal kinases including LCK and ZAP-70, thereby attenuating downstream PI3K/AKT and NF-??B pathways and reducing transcription of IL-2 and other effector cytokines. PD-L1 expression is transcriptionally regulated by STAT3 and NF-??B downstream of numerous upstream stimuli, including interferon-gamma (IFNG), epidermal growth factor receptor (EGFR) signaling, hypoxia-inducible factor 1-alpha (HIF1A), and PTEN loss. Additionally, PD-L1 protein stability is modulated by interactions with CMTM6 and CMTM4. Knockout of CD274 abrogates this inhibitory signaling, relieving suppression of T cell proliferation and cytokine production.
In the context of gastric adenocarcinoma, PD-L1 upregulation is frequently associated with immune escape and poor prognosis. The CD274 Knockout AGS Polyclonal Cells therefore constitute a valuable isogenic system for dissecting the role of PD-L1 in gastric cancer immune evasion. By eliminating PD-L1?Cmediated T cell inhibition, this model enables researchers to assess how tumor cells modulate the immune synapse and to identify compensatory mechanisms that may arise upon checkpoint blockade. The polyclonal nature of the knockout population reflects a range of editing mutations, closely mimicking the genetic heterogeneity often encountered in tumor specimens.
These knockout cells are suited for a broad array of experimental approaches, including western blotting and RT-qPCR for PD-L1 expression analysis, flow cytometry for surface PD-L1 quantification, and immunofluorescence imaging. Functional studies can employ T cell co-culture systems, with readouts such as IL-2 and IFN-gamma ELISA or T cell proliferation assays, to evaluate restoration of anti-tumor immunity. Moreover, this model supports xenograft tumor growth assays to study tumorigenesis in vivo, PD-L1 inhibitor screening, and dissection of the tumor microenvironment. For further details, please contact Ascent Research.
