The IDO1 Knockout LoVo Polyclonal Cells are a CRISPR/Cas9-edited polyclonal population of LoVo human colorectal adenocarcinoma cells harboring a targeted disruption of the IDO1 gene. This polyclonal pool, generated via CRISPR/Cas9-mediated gene knockout, provides a loss-of-function model for studying IDO1 biology without clonal selection limitations. It is suitable for assays requiring population-level analyses of immune checkpoint function and tryptophan metabolism.
The parental LoVo cell line is an epithelial model originally derived from a metastatic left supraclavicular lymph node of a 56-year-old Caucasian male with colon adenocarcinoma. LoVo cells retain key features of colorectal adenocarcinoma and are widely employed for investigating tumor cell biology, drug sensitivity, and the tumor microenvironment, making them an ideal host for IDO1 ablation studies.
IDO1 encodes indoleamine 2,3-dioxygenase, the rate-limiting enzyme that converts tryptophan to kynurenine in the kynurenine pathway. Its expression is induced by interferon-gamma (IFNG), tumor necrosis factor (TNF), and interleukin-1 beta (IL1B). Downstream, kynurenine activates the aryl hydrocarbon receptor (AHR) and GCN2 kinase while inhibiting mTOR, leading to FOXP3 induction and regulatory T cell differentiation. IDO1 activity requires heme as a cofactor and is regulated by SOCS3 and SHP-1 interactions. Collectively, IDO1 functions as an immune checkpoint that suppresses effector T cells and promotes immune tolerance.
In LoVo colorectal adenocarcinoma cells, IFNG-induced IDO1 expression creates an immunosuppressive microenvironment through tryptophan depletion and kynurenine generation. Knocking out IDO1 disrupts this axis, enabling researchers to directly examine restored T cell proliferation in co-culture assays, altered kynurenine-to-tryptophan ratios via LC-MS/MS, and changes in p-GCN2 and FOXP3 levels by Western blot. This model is particularly relevant for evaluating IDO1 inhibitor efficacy, including combination immunotherapy strategies.
Applications include tumor immunology, metabolic profiling, and drug screening. Representative assays encompass T cell suppression co-cultures, flow cytometry for Treg and activation markers, RT-qPCR for IDO1 and FOXP3, ELISA for kynurenine, and dose-response studies with epacadostat. The polyclonal knockout cells also support immune tolerance and autoimmune disease research. For further information, contact Ascent Research.
