The CD274 Knockout NCI-H1703 Polyclonal Cells are a CRISPR/Cas9-edited polyclonal population of NCI-H1703 human lung squamous cell carcinoma cells with targeted disruption of the CD274 gene, which encodes the immune checkpoint ligand PD-L1. This heterogeneous knockout pool, generated without single-cell cloning, provides a robust loss-of-function model for studying PD-L1-mediated immune regulation in a genetically diverse, near-endogenous context.
The parental NCI-H1703 cell line is an adherent epithelial model derived from a primary lung squamous cell carcinoma of a smoking patient. It serves as a well-established in vitro system for non-small cell lung cancer (NSCLC) research, specifically representing the squamous cell carcinoma subtype. These cells retain key tumor characteristics and are extensively used to probe NSCLC biology and therapeutic responses.
CD274 (PD-L1) functions as an immune checkpoint protein that binds the PD-1 receptor on T cells, transmitting inhibitory signals that suppress T cell proliferation and effector functions. PD-1 engagement activates SHP2 phosphatase, which attenuates downstream PI3K?CAKT and JAK?CSTAT pathways. CD274 expression is induced by IFNG via JAK?CSTAT1?CIRF1 signaling and is modulated by oncogenic pathways including MYC and PTEN/PI3K/AKT. PD-L1 also interacts with CD80 and shares receptor overlap with PD-L2. Key molecular nodes involved include PD-L1, PD-1, SHP2, PI3K, AKT, JAK, STAT1, and NF-??B.
In NCI-H1703 cells, which endogenously express PD-L1, knockout of CD274 eliminates this inhibitory interaction, enabling dissection of PD-L1??s role in immune evasion within a squamous NSCLC context. This model is especially relevant for studying how PD-L1 loss influences T cell activation, cytokine secretion, and tumor cell killing, and it provides a platform to investigate mechanisms of resistance to PD-1/PD-L1 blockade.
These knockout cells are suitable for co-culture assays with PBMCs or T cells to measure IFN-?? release by ELISA, flow cytometric analysis of PD-L1 expression and T cell activation markers, and PD-1/PD-L1 binding inhibition studies. They support gene expression profiling by RT-qPCR and western blotting to probe compensatory signaling. Applications include drug screening for checkpoint inhibitors, tumor microenvironment modeling, and T cell exhaustion research. For more information, please contact Ascent Research.
