Description

The CTNNBIP1 Knockout HL-60 Cell Line is a CRISPR/Cas9-edited human cell model in which the coding sequence of CTNNBIP1 has been disrupted to produce a loss-of-function allele. Derived from the HL-60 promyelocytic leukemia line, this knockout cell line provides a genetically defined system for analyzing ICAT (inhibitor of ??-catenin and TCF), a key negative regulator of the canonical Wnt signaling axis. By abolishing endogenous CTNNBIP1 expression, the model allows researchers to interrogate the functional consequences of removing this repressive checkpoint on ??-catenin/TCF-mediated transcription in a leukemic background.

The parental HL-60 cell line was established from the peripheral blood of a 36-year-old female diagnosed with acute promyelocytic leukemia (AML M3 subtype). HL-60 cells are extensively used as an in vitro model for myeloid biology because they can be induced to differentiate into granulocytic or monocytic lineages following treatment with retinoic acid, dimethyl sulfoxide, or phorbol esters. They harbor the t(15;17)(q22;q21) translocation that generates the PML-RARA fusion protein, which arrests cells at the promyelocyte stage. This genetic background offers a unique context to explore how aberrant signaling pathways, including the Wnt cascade, interact with the differentiation block and contribute to leukemogenesis.

CTNNBIP1 encodes ICAT, an inhibitor of ??-catenin/TCF-mediated transcription. ICAT binds the armadillo repeats of ??-catenin (CTNNB1) and blocks its association with TCF/LEF factors such as TCF7L2 and LEF1. In canonical Wnt signaling, WNT3A stimulation activates Frizzled/LRP6 receptors, leading to DVL2-mediated inhibition of the AXIN1-APC-GSK3B destruction complex and stabilization of ??-catenin. Nuclear ??-catenin partners with TCF7L2 and LEF1 to induce targets including MYC, CCND1, and AXIN2. ICAT counteracts this process by competing for ??-catenin binding, maintaining transcriptional repression. Knockout of CTNNBIP1 eliminates this brake, leading to sustained ??-catenin/TCF signaling.

Within the HL-60 leukemia model, CTNNBIP1 knockout provides a means to directly assess the contribution of ICAT to the control of ??-catenin activity. Sustained ??-catenin/TCF signaling has been implicated in the maintenance of leukemia stem cells and in the pathogenesis of AML, often cooperating with oncoproteins such as PML-RARA. By comparing knockout and wild-type HL-60 cells, investigators can determine whether loss of ICAT alters proliferation kinetics, differentiation capacity, or sensitivity to chemotherapeutic agents. This system is thus valuable for elucidating the mechanisms by which Wnt pathway dysregulation influences myeloid transformation and for validating ??-catenin/TCF as a therapeutic target in leukemia.

This cell line supports diverse applications: quantitative Wnt pathway assessment via TOP/FOP Flash reporter assays; gene expression analysis of targets (MYC, CCND1, AXIN2) by RT-qPCR; protein-level validation by Western blot; and differentiation phenotyping by flow cytometry for CD11b and CD14. It is also amenable to RNA-seq for transcriptome-wide discovery and high-throughput chemical screening for Wnt modulators. The CTNNBIP1 Knockout HL-60 Cell Line is an essential resource for dissecting Wnt-driven leukemogenesis and evaluating therapeutic candidates. For further information, please contact Ascent Research.