The CD274 Knockout MCF-7 Polyclonal Cells consist of a CRISPR/Cas9-edited polyclonal population derived from the MCF-7 human mammary epithelial adenocarcinoma cell line, bearing targeted disruption of the CD274 gene, which encodes the immune checkpoint ligand programmed death-ligand 1 (PD-L1). This polyclonal knockout pool provides a heterogeneous collection of loss-of-function alleles, enabling robust investigation of PD-L1-mediated immune evasion without the constraints of clonal selection.
The parental MCF-7 line was established from the pleural effusion of a 69-year-old Caucasian female with metastatic breast adenocarcinoma and exhibits adherent epithelial morphology. These cells are estrogen receptor-positive, hormone-sensitive, and representative of the luminal A molecular subtype, providing a clinically relevant model for breast cancer biology and endocrine therapy research.
CD274 encodes PD-L1, a type I transmembrane protein that binds PD-1 on activated T cells, recruiting SHP-2 phosphatase to dephosphorylate TCR signaling molecules such as ZAP70 and LCK, thereby attenuating PI3K/Akt pathway activity and IL-2 production. PD-L1 expression is regulated by IFN-?? via JAK-STAT signaling, involving STAT1, STAT3, and IRF1, as well as by NF-??B, MYC, and HIF-1??. PD-L1 also interacts with CD80 and signals through ITIM/ITSM motifs. Disruption of CD274 abrogates this central immune checkpoint axis, enabling detailed dissection of T-cell suppression mechanisms.
In MCF-7 cells, CD274 knockout allows examination of PD-L1 function within a hormone-responsive breast cancer context. Low basal PD-L1 levels can be induced by IFN-??, mimicking adaptive immune evasion. This model facilitates interrogation of potential crosstalk between estrogen receptor signaling and immune checkpoint pathways, and enables studies of PD-L1??s role in tumor-intrinsic processes such as proliferation, apoptosis, and migration, relevant to endocrine therapy resistance.
These polyclonal knockout cells support diverse applications, including immune checkpoint blockade research, PD-L1 biomarker analysis, drug resistance studies, and tumor microenvironment modulation. Representative assays include flow cytometry for PD-L1 surface expression, western blotting, RT-qPCR, T-cell suppression co-cultures, immunofluorescence, IFN-?? stimulation, apoptosis and migration/invasion assays, as well as ChIP-qPCR for transcription factor binding. For further product details, please contact Ascent Research.
