The ARHGEF18 Knockout HT29 Polyclonal Cells represent a CRISPR/Cas9-edited polyclonal knockout cell population derived from the HT29 colorectal adenocarcinoma line, engineered to disrupt the ARHGEF18 gene. This loss-of-function model eliminates ARHGEF18 protein expression, providing a powerful tool to dissect RhoA guanine nucleotide exchange factor (GEF) activity in a disease-relevant epithelial background. As a heterogeneous knockout population, it recapitulates gene disruption without clonal selection artifacts, enabling robust phenotype analysis across a pool of edited alleles.
The HT29 host cell line is a well-characterized model of human colorectal adenocarcinoma, featuring a TP53 R273H mutation and microsatellite stability. These cells form polarized epithelial monolayers and differentiate into absorptive enterocyte-like cells under appropriate conditions, making them a standard system for studying intestinal epithelial barrier function, absorption, and tight junction biology. Their epithelial origin and inherent oncogenic background provide a physiologically relevant platform for investigating the interplay between adhesion complexes, cytoskeletal dynamics, and cancer cell behavior.
ARHGEF18 functions as a dedicated RhoA-specific GEF that transduces signals from G protein-coupled receptors (GPCRs) coupled to G??12/13 heterotrimeric G proteins, as well as from integrin- and cadherin-mediated adhesion complexes. Upon activation, ARHGEF18 catalyzes GDP/GTP exchange on RhoA, triggering downstream effectors such as ROCK1/2 and mDia. This signaling axis drives myosin light chain (MLC) phosphorylation via ROCK-mediated inhibition of myosin phosphatase, leading to actomyosin contractility, actin stress fiber assembly, and junctional actomyosin remodeling. ARHGEF18 physically interacts with tight junction scaffolding proteins ZO-1 (TJP1), ZO-2 (TJP2), and cingulin (CGN), tethering RhoA activation to intercellular junctions and thereby coordinating cytoskeletal responses with epithelial architecture.
In the HT29 context, ARHGEF18 knockout profoundly impacts epithelial homeostasis. Loss of ARHGEF18-mediated RhoA activation at cell?Ccell contacts disrupts tight junction and adherens junction integrity, manifesting as compromised barrier function, increased paracellular permeability, and altered actin cytoskeleton organization. These changes mirror early steps in colorectal cancer progression, where diminished junctional adhesion facilitates tumor cell dissociation, migration, and invasion. Consequently, this polyclonal knockout model enables direct interrogation of how RhoA signaling through ARHGEF18 maintains epithelial barrier properties and how its dysfunction contributes to malignancy-associated phenotypes.
This product is suited for diverse applications, including mechanistic studies of RhoA/ROCK/MLC signaling, epithelial barrier integrity assays such as transepithelial electrical resistance (TEER) and FITC-dextran permeability, high-content screening for RhoA pathway modulators, and colorectal cancer metastasis research using wound-healing and Transwell invasion assays. Complementing these functional assays, the model supports biochemical analyses like RhoA activation G-LISA, Western blotting for phospho-MLC, and immunofluorescence imaging of ZO-1 and F-actin localization. Cell viability (MTT) and apoptosis (Annexin V) assays further facilitate drug response profiling. For additional information or to discuss custom applications, please contact Ascent Research.
