The IDO1 Knockout SK-OV-3 polyclonal cells are a CRISPR/Cas9-edited polyclonal knockout cell population in which the indoleamine 2,3-dioxygenase 1 (IDO1) gene has been disrupted. This model is generated by transiently delivering CRISPR/Cas9 components into the human ovarian adenocarcinoma cell line SK-OV-3, yielding a heterogeneous pool of edited cells ideally suited for functional genomics studies in a cancer-relevant background.
The host cell line SK-OV-3 is a widely used model of human epithelial ovarian cancer, originally established from the ascites of a 64-year-old Caucasian female with ovarian adenocarcinoma. These cells exhibit adherent growth, harbor TP53 mutations, and display molecular features consistent with high-grade serous carcinoma. SK-OV-3 cells are extensively characterized for tumorigenicity, drug sensitivity, and expression of epithelial-mesenchymal markers, providing a robust platform for ovarian cancer research.
IDO1 is an interferon-gamma (IFNG)-inducible enzyme that catalyzes the first and rate-limiting step of tryptophan degradation along the kynurenine pathway. Its expression is transcriptionally upregulated by cytokines such as IFNG, tumor necrosis factor (TNF), and interleukin-1 (IL1), acting through transcription factors including STAT1, IRF1, NFKB, and AP-1. The product, kynurenine, functions as an endogenous agonist of the aryl hydrocarbon receptor (AhR), initiating immunosuppressive transcriptional programs that promote T-cell anergy, expansion of regulatory T cells (Tregs), activation of GCN2 kinase, and suppression of mTOR signaling. IDO1 also interacts with SOCS proteins and heme cofactors, and works in concert with downstream kynurenine pathway enzymes like KMO and KYNU. Together, this signaling axis positions IDO1 as a central regulator of immune tolerance and tumor immune evasion.
In the ovarian cancer context, IDO1 is often exploited by tumors to deplete local tryptophan and generate kynurenine, fostering an immunotolerant microenvironment. The SK-OV-3 knockout polyclonal population provides an isogenic system to dissect the functional consequences of IDO1 loss. Researchers can directly compare knockout and parental cells to assess changes in tryptophan metabolism, immune cell modulation in co-culture, and alterations in downstream effector pathways including AhR-regulated gene networks and mTOR activity. This model is particularly valuable for validating IDO1-dependent immune checkpoints and studying crosstalk with other immunoregulatory pathways.
Representative applications include investigation of tumor immune evasion mechanisms in ovarian cancer, screening and profiling of IDO1 inhibitors, and characterization of the kynurenine pathway using assays such as HPLC/LC-MS for kynurenine-to-tryptophan ratio, Western blotting and RT-qPCR for IDO1 and pathway targets, and co-culture with PBMCs or T cells to evaluate immunosuppressive function. The polyclonal knockout cells are also suitable for high-throughput compound screening and transcriptomic studies (RNA-seq). For additional technical details or to inquire about custom cell engineering, please contact Ascent Research.
