The IDO1 Knockout NCI-H1703 Polyclonal Cells constitute a CRISPR/Cas9-edited polyclonal knockout cell population derived from the NCI-H1703 lung squamous cell carcinoma line. Disruption of the IDO1 gene eliminates indoleamine 2,3-dioxygenase-1 activity, creating a loss-of-function model for studying immune checkpoint biology in non-small cell lung cancer (NSCLC). The polyclonal format reflects heterogeneous gene disruption, avoiding clonal selection biases and more closely mimicking the variable knockout efficiencies encountered in therapeutic settings.
The parental NCI-H1703 cell line was established from a squamous cell carcinoma of the lung in a 54-year-old male smoker. It displays adherent epithelial morphology and is a well-characterized model for squamous NSCLC, retaining key genetic alterations and signaling profiles of this tumor type. Its tumor-derived origin and compatibility with varied assays make it an ideal host for dissecting cancer-intrinsic immune regulatory pathways.
IDO1 catalyzes the initial and rate-limiting step of tryptophan degradation along the kynurenine pathway, generating kynurenine and depleting local tryptophan. Expression is strongly induced by IFN-?? via JAK/STAT, with additional regulation by TNF-??, IL-1??, and TGF-?? through NF-??B and IRFs. Kynurenine acts as an endogenous AhR ligand, driving T-cell anergy, apoptosis, and FOXP3/STAT3-mediated Treg differentiation. IDO1 also engages GCN2 and mTOR cascades, and functionally interacts with checkpoint molecules PD-L1 and CTLA-4, integrating metabolic and immune regulatory signals to promote immune tolerance.
In NCI-H1703 lung carcinoma cells, IDO1 contributes to local immunosuppression, fostering tumor immune evasion. This knockout model allows dissection of tumor cell-autonomous IDO1 functions, independent of host immune cell-derived enzyme, and is valuable for examining how loss of enzyme activity alters kynurenine production and downstream AhR signaling. It is particularly relevant for studying the interplay between tumor metabolism and immune cell function in the NSCLC microenvironment.
These polyclonal knockout cells are suitable for numerous research applications in cancer immunotherapy. They enable pharmacological testing of IDO1 inhibitors (e.g., epacadostat) and combination regimens with anti-PD-1 agents. Common assays include immunoblotting and RT-qPCR for IDO1, HPLC/MS-based kynurenine measurement, T-cell proliferation co-cultures, flow cytometric analysis of immune markers (PD-L1, CTLA-4, FOXP3), and cytokine profiling. Transcriptomics (RNA-seq) can reveal pathway-wide changes, and in vivo tumor xenografts can assess growth and immune infiltration. For additional information or to discuss specialized protocols, please contact Ascent Research.
