The CD274 Knockout NCI-H1299 Polyclonal Cells represent a CRISPR/Cas9-edited polyclonal knockout population of NCI-H1299 human lung adenocarcinoma cells, engineered for targeted disruption of the CD274 gene locus. This polyclonal format provides a heterogeneous cell pool derived from a bulk-edited population, offering a robust model for functional studies. The CD274 gene encodes programmed death-ligand 1 (PD-L1), a critical immune checkpoint molecule. By eliminating PD-L1 expression, this model enables investigation of PD-L1-dependent immune evasion and restoration of anti-tumor T-cell responses, while genetic diversity inherent in the polyclonal population can be advantageous for certain experimental designs.
The parental NCI-H1299 cell line is an adherent epithelial cell line established from a lymph node metastasis of a non-small cell lung carcinoma (NSCLC). It serves as a widely used model for metastatic lung adenocarcinoma. Notably, NCI-H1299 cells are deficient in the tumor suppressor p53, a common feature of aggressive lung cancers, making them particularly relevant for studies on tumor progression and therapeutic resistance. Their metastatic origin and p53-null status contribute to a highly tumorigenic phenotype, suitable for both in vitro and in vivo oncology applications.
PD-L1 functions as a transmembrane ligand that binds PD-1 on T cells, delivering co-inhibitory signals that suppress TCR-mediated proliferation, cytokine production, and cytotoxicity. Downstream of PD-1, SHP-2 phosphatase dephosphorylates key mediators such as ZAP70 and LCK, thereby inhibiting NFAT-driven IL-2 production. PD-L1 expression is tightly regulated by IFN-?? via the JAK1/STAT1 pathway, and by oncogenic signals including STAT3, c-Myc, HIF-1??, and NF-??B. CD274 knockout consequently disrupts this ligand?Creceptor interaction and the associated inhibitory signaling cascade.
In the NCI-H1299 lung cancer setting, PD-L1-mediated immune checkpoint signaling is a central mechanism of tumor immune evasion. Ablation of CD274 in these p53-deficient cells creates an isogenic system to dissect PD-L1-specific contributions to the immunosuppressive tumor microenvironment without clonal bias, given the polyclonal background. This model is especially useful for studying how loss of PD-L1 affects tumor-immune cross-talk, as NCI-H1299 cells are known to upregulate PD-L1 upon IFN-?? stimulation. Researchers can directly assess functional outcomes of PD-L1 depletion on T-cell activation, cytokine secretion, and tumor killing in co-culture assays.
The CD274 Knockout NCI-H1299 Polyclonal Cells are applicable to a range of immuno-oncology studies. They can be used in co-culture with PBMCs or engineered T cells to measure restoration of T-cell proliferation and cytotoxicity via flow cytometry, ELISA, or live-cell imaging. IFN-?? treatment allows examination of PD-L1-independent responses. The model is ideal for screening small-molecule PD-L1 inhibitors or therapeutic antibodies. In vivo, these cells enable xenograft studies in humanized mouse models to evaluate tumor growth and immune infiltration. Standard readouts include PD-L1 expression by western blot and RT-qPCR, and T-cell activation markers such as CD69 and CD25. For further technical details, please contact Ascent Research.
