IL4I1 Knockout HuH-7 Cell Line

The IL4I1 Knockout HuH-7 Cell Line is a genetically modified human hepatocellular carcinoma cell product in which the interleukin-4-induced gene 1 (IL4I1) locus has been disrupted via CRISPR/Cas9-mediated gene editing. This knockout cell line is provided as a stable, engineered cell population and is designed to enable loss-of-function studies targeting the IL4I1 enzyme. The gene disruption abrogates the expression of the L-amino acid oxidase IL4I1, a secreted metabolic immune modulator, and offers a defined genetic background for investigating its roles in tumor immune evasion and metabolic reprogramming. The cell line retains the characteristic features of the parental HuH-7 cells while serving as a robust platform for mechanistic and pharmacological analyses.

HuH-7 is an adherent epithelial cell line established from a well-differentiated human hepatocellular carcinoma. These cells harbor a mutant p53 tumor suppressor gene, are negative for hepatitis B virus, and are widely utilized in liver cancer biology, hepatitis C virus replication studies, and drug metabolism research. The parental HuH-7 line is a standard model in hepatocellular carcinoma research, owing to its well-characterized growth properties, tumorigenicity, and permissiveness to HCV infection. The knockout derivative maintains the established heritage of HuH-7, providing a familiar and reliable experimental system for investigators studying liver cancer and viral pathogenesis.

IL4I1 encodes an extracellular L-amino acid oxidase that preferentially catalyzes the oxidative deamination of phenylalanine, tyrosine, and tryptophan, producing hydrogen peroxide and kynurenine. The enzyme is transcriptionally regulated by IL-4/STAT6 signaling, NF-??B, and interferon-gamma. Downstream, the kynurenine metabolite functions as an endogenous agonist of the aryl hydrocarbon receptor (AHR), which in turn modulates expression of immunosuppressive mediators including IL-10, TGF-??, and the immune checkpoint molecule PD-L1, while also promoting FOXP3 expression and regulatory T-cell differentiation. Through this kynurenine?CAHR axis, IL4I1 plays a critical role in dampening Th1 effector responses and fostering an immune-tolerant microenvironment in tumors. Additional interacting molecular partners include the aromatic amino acid substrates themselves, linking the enzyme to core metabolic and immune regulatory networks.

In hepatocellular carcinoma, IL4I1 expression has been implicated in facilitating immune escape by suppressing local T-cell activity and inducing regulatory T-cell populations. The IL4I1 Knockout HuH-7 Cell Line therefore represents a valuable tool for dissecting the contribution of IL4I1-dependent kynurenine production to hepatic tumor immune privilege. Loss of IL4I1 is expected to reduce kynurenine secretion, attenuate AHR activation, and impair the induction of downstream immunosuppressive programs, enabling researchers to directly examine how this metabolic enzyme shapes the tumor?Cimmune interface in a liver cancer context. This model can be paired with wild-type HuH-7 controls to compare immune cell behavior and cytokine profiles in co-culture systems.

The knockout line is suited for a wide range of applications, including hepatocellular carcinoma immune evasion studies, dissection of the kynurenine/AHR signaling pathway, and screening of small-molecule IL4I1 inhibitors. Representative assays include kynurenine ELISA to quantify metabolite secretion, AHR luciferase reporter assays for pathway activity, T-cell proliferation and suppression assays, flow cytometric analysis of regulatory T-cell markers (FOXP3, CD25), western blotting for IDO1 and PD-L1, and RT-qPCR for IL-10 and TGF-??. Co-culture experiments with peripheral blood mononuclear cells or purified T cells can further assess the functional impact of IL4I1 loss on T-cell responses. For additional technical information or to request a detailed protocol, please contact Ascent Research.