The ABCB1 Knockout CAL-27 Polyclonal Cells are a CRISPR/Cas9-edited polyclonal knockout cell population carrying a targeted disruption of the ABCB1 gene in the human oral squamous cell carcinoma line CAL-27. This heterogeneous pool enables loss-of-function studies of P-glycoprotein (P-gp), the ABCB1-encoded multidrug transporter, without single-cell cloning. The model is suitable for population-based assays to investigate multidrug resistance mechanisms and assess strategies to overcome chemoresistance.
Derived from a tongue squamous cell carcinoma, the CAL-27 cell line is a well-established model for oral cancer research and is notorious for its multidrug resistance phenotype, partially driven by endogenous ABCB1 expression. CAL-27 cells display aggressive growth and are routinely used to study head and neck cancer biology and therapeutic response. Disrupting ABCB1 in this background provides a contextually relevant system for dissecting P-gp-mediated drug efflux.
P-glycoprotein (ABCB1) is an ATP-dependent efflux pump that exports diverse chemotherapeutic agents and xenobiotics, reducing intracellular drug concentrations. Its transcription is regulated by nuclear receptors NR1I2 (PXR) and NR1I3 (CAR), as well as by HIF1A, NFKB1, and TP53, with additional input from MAPK and AKT1 signaling. ATP hydrolysis drives substrate translocation, and P-gp function is modulated by interactions with caveolin-1, ezrin, and the actin cytoskeleton. Downstream effects include apoptosis inhibition and cancer stem cell maintenance, contributing to multidrug resistance. Other transporters such as ABCC1 and ABCG2 are also part of this network.
Knockout of ABCB1 eliminates P-gp expression, impairing drug efflux and potentially reversing resistance. This polyclonal model captures population-level heterogeneity, making it suitable for studying drug transport kinetics, identification of P-gp substrates, and screening resistance-modifying agents. It also enables investigation of compensatory upregulation of alternative ABC transporters upon ABCB1 loss, providing a comprehensive platform for multidrug resistance research.
Applications for the ABCB1 Knockout CAL-27 Polyclonal Cells encompass functional transporter assays with fluorescent substrates such as rhodamine 123, dose-response cytotoxicity studies using MTT or similar viability readouts, and intracellular drug quantitation via flow cytometry or LC-MS/MS. The cells are also suitable for probing P-gp-dependent apoptosis resistance, performing migration and invasion assays to study metastatic potential, and validating candidate P-gp inhibitors. Western blotting can confirm ABCB1 knockout and monitor pathway alterations. For further information or to discuss specialized assays, please contact Ascent Research.
