The IDO1 Knockout CAL-27 Polyclonal Cells consist of a CRISPR/Cas9-edited polyclonal population of CAL-27 oral squamous cell carcinoma cells with targeted disruption of the IDO1 gene. This product offers a loss-of-function model for studying IDO1??s immunoregulatory role without clonal selection, preserving genetic heterogeneity for robust phenotypic analysis.
CAL-27 is an aneuploid epithelial cell line established from a 56-year-old male with tongue squamous cell carcinoma. Tumorigenic in nude mice and widely used in head and neck cancer biology and drug testing, this host provides a clinically relevant platform to examine cell-autonomous and microenvironmental functions of IDO1.
IDO1 catalyzes the initial, rate-limiting step of tryptophan degradation along the kynurenine pathway, producing N-formylkynurenine rapidly converted to kynurenine, kynurenic acid, and quinolinic acid. Transcriptionally induced by interferon-gamma (IFNG) through JAK-STAT1 and IRF1, IDO1 is further regulated by interleukin-1 beta, tumor necrosis factor, and prostaglandin E2. The enzyme incorporates a heme cofactor and interacts with SOCS3 and SHP-1. Kynurenine acts as an endogenous ligand for the aryl hydrocarbon receptor (AhR), upregulating CYP1A1 and TGFB, which promotes na?ve T-cell differentiation into FOXP3+ regulatory T cells. Simultaneously, tryptophan depletion activates GCN2 kinase, suppressing mTOR signaling and inhibiting effector T-cell proliferation. This dual mechanism underpins IDO1??s potent immunosuppressive function.
In oral squamous cell carcinoma, IDO1-mediated immune suppression facilitates tumor immune evasion, highlighting its relevance as a therapeutic target. The IDO1 Knockout CAL-27 Polyclonal Cells allow researchers to dissect IDO1-specific contributions to OSCC biology. Experiments can evaluate how IDO1 disruption reduces kynurenine secretion, dampens AhR activation, and impairs regulatory T-cell induction, while restoring T-cell effector function. This model also enables comparison of wild-type and knockout CAL-27 cells for changes in proliferation, invasion, and response to chemotherapeutics or IDO1 inhibitors within a tumor microenvironment context.
Typical assays encompass co-culture with human PBMCs to quantify T-cell suppression by CFSE dilution or activation markers, metabolic profiling of tryptophan and kynurenine via HPLC or colorimetric methods, and immunoblotting or immunofluorescence for IDO1, STAT1, and FOXP3. The polyclonal population is suitable for IDO1 inhibitor dose-response studies, RNA-seq analyses of downstream targets, and rescue experiments with reconstituted IDO1. For additional information or technical consultation, please contact Ascent Research.
