The ABCB1 Knockout DLD-1 Polyclonal Cells are a CRISPR/Cas9-edited polyclonal knockout cell population targeting the ABCB1 gene in the human colorectal adenocarcinoma DLD-1 cell line. This loss-of-function model ablates P-glycoprotein expression, offering a controlled system to study multidrug resistance mechanisms. The polyclonal format provides a heterogeneous pool of edited cells, minimizing clonal bias and ensuring comprehensive representation of knockout genotypes.
The parental DLD-1 cell line was established from a colorectal adenocarcinoma of a male patient, classified as Dukes’ type C. It is characterized by mutations in TP53, APC, KRAS, and PIK3CA, and maintains microsatellite stability (MSS). DLD-1 is a widely used model in colorectal cancer research for dissecting tumor biology, drug resistance pathways, and oncogenic signaling cascades.
ABCB1 encodes P-glycoprotein, an ATP-binding cassette transporter that functions as an efflux pump for xenobiotics and chemotherapeutic agents, including doxorubicin, vinblastine, and paclitaxel. Its transcriptional regulation is mediated by the pregnane X receptor (PXR/NR1I2), constitutive androstane receptor (CAR), and transcription factors NF-??B, p53, YAP, and HIF-1??, often downstream of Wnt/??-catenin signaling. At the plasma membrane, P-glycoprotein associates with the ERM protein complex (ezrin, radixin, moesin) and caveolin-1, which facilitate its localization and stability. Overexpression of ABCB1 reduces intracellular drug accumulation, increases IC50 values, and suppresses apoptosis, thereby driving chemoresistance.
In the DLD-1 colorectal adenocarcinoma context, ABCB1 is a critical mediator of drug resistance, reflecting clinical scenarios. Genetic disruption of ABCB1 resensitizes these cells to substrate chemotherapeutics and permits investigation of P-glycoprotein-independent resistance mechanisms. This polyclonal knockout population serves as a vital tool for studying adaptive responses and for screening compounds that target alternative efflux pathways or signaling nodes.
Researchers can utilize this model for functional transporter assays such as Rhodamine 123 efflux kinetics, drug sensitivity profiling to determine IC50 shifts, and flow cytometry-based measurement of intracellular drug accumulation. Molecular analyses include Western blotting for P-glycoprotein, RT-qPCR for ABCB1 transcript levels, and luciferase reporter assays to probe PXR- or NF-??B-mediated MDR1 promoter activation. Additional applications encompass chemosensitization screens, pharmacokinetic modeling, and mechanistic studies of transcriptional regulation in colorectal cancer. For further information and technical support, please contact Ascent Research.
