The ABCC4 Knockout HeLa Polyclonal Cells are a CRISPR/Cas9-edited polyclonal knockout population with targeted disruption of the ABCC4 (MRP4) gene in human HeLa epithelial cells. This loss-of-function model eliminates ABCC4-mediated efflux, providing a tool for studying cyclic nucleotide signaling, drug resistance, and inflammatory mediator release.
HeLa cells are an immortalized cervical adenocarcinoma line with epithelial characteristics, extensively used in cancer and signal transduction research. Their robust growth and well-defined transporter expression make them an ideal host for investigating ABCC4-dependent pharmacology and cellular transport.
ABCC4 is an ATP-binding cassette transporter that extrudes cyclic nucleotides (cAMP, cGMP), prostaglandin E2, leukotriene C4, urate, and xenobiotics. Transcriptionally activated by NFE2L2 (NRF2) under oxidative stress and by constitutive androstane receptor (CAR) upon xenobiotic exposure, ABCC4 interacts with PDZK1, NHERF1, and ERM proteins for membrane localization. Its activity directly regulates intracellular cAMP and cGMP levels, modulating PKA/CREB and PKG signaling cascades. By controlling the efflux of inflammatory mediators, ABCC4 influences prostaglandin and leukotriene signaling pathways. Knockout of ABCC4 thus disrupts these interconnected networks, raising second messenger concentrations and altering kinase and transcription factor activation.
In HeLa cells, ABCC4 knockout abolishes the primary efflux route for cyclic nucleotides and drugs, leading to cAMP/cGMP accumulation, enhanced PKA/PKG activity, and increased CREB phosphorylation. The loss of drug efflux sensitizes cells to chemotherapeutic agents, highlighting its role in multidrug resistance. Additionally, removal of ABCC4 alters NRF2-mediated oxidative stress responses and urate transport, making this model valuable for studying antioxidant defense and hyperuricemia. The epithelial origin further enables exploration of transporter function in barrier tissues.
Applications include drug resistance studies using substrate efflux assays (3H-cAMP, calcein-AM) and cytotoxicity tests (MTT, colony formation). cAMP/cGMP signaling is assessed via ELISA, PKA/PKG activity assays, and CREB phosphorylation western blotting. Transporter substrate identification employs HPLC-MS and transwell assays, while flow cytometric drug accumulation monitors intracellular retention. Inflammatory modulation is examined through PGE2 and LTC4 quantification, and NRF2 target gene expression is measured by RT-qPCR. ATPase activity assays further characterize ABCC4-substrate interactions. For additional details, contact Ascent Research.
