The APOM Knockout A-549 Polyclonal Cells are a CRISPR/Cas9-edited polyclonal population derived from A-549 human lung adenocarcinoma cells, with targeted disruption of the APOM gene. This loss-of-function model abolishes apolipoprotein M production, enabling studies of its role in sphingosine-1-phosphate (S1P) transport and signaling. The heterogeneous knockout pool, generated without single-cell cloning, is maintained under standard conditions and validated for APOM disruption at the population level, providing a robust tool for molecular and cellular analyses.
The parental A-549 cell line originated from lung adenocarcinoma tissue of a 58-year-old Caucasian male and serves as a model of human alveolar type II epithelial cells. These cells form adherent monolayers, express key epithelial markers, and mimic pulmonary barrier properties. They are widely employed in cancer biology, drug metabolism, and epithelial pathophysiology research. The A-549 genetic background, including KRAS and TP53 mutations, offers a tumorigenic context for exploring APOM function in lung cancer-associated lipid signaling.
APOM is an HDL-associated apolipoprotein that chaperones S1P, a bioactive sphingolipid. APOM-S1P complexes on HDL bind to endothelial S1PR1, activating Gi-mediated Rac1 and PI3K/Akt signaling to stabilize VE-cadherin junctions and promote barrier integrity via eNOS-dependent mechanisms. APOM expression is regulated by transcription factors HNF1A, LXRs, and PPARs, and responds to insulin and glucose levels. Key interacting partners include apoA-I on HDL and albumin. Downstream effectors include S1PR1, S1PR3, Akt, eNOS, and Rac1.
In A-549 cells, APOM knockout disrupts S1P delivery, impairing autocrine/paracrine signaling that affects monolayer permeability, junctional architecture, and survival pathways. Although A-549 cells are epithelial, they express S1P receptors and exhibit barrier-like features, making them suitable for studying epithelial barrier regulation. Loss of APOM may reduce Rac1 and Akt activation, compromising VE-cadherin organization and increasing susceptibility to inflammatory or apoptotic stimuli. This model is particularly relevant for investigating S1P-driven processes in the tumor microenvironment.
These polyclonal knockout cells support S1P secretion quantification by ELISA, permeability assays (TEER), and immunofluorescence of junctional proteins like VE-cadherin and ZO-1. They enable apoptosis and cytokine profiling (e.g., IL-6, IL-8) under various stimuli, as well as drug screenings for S1P receptor modulators. Additional applications include RT-qPCR analysis of APOM mRNA, western blotting of phospho-Akt and eNOS, and metabolic regulation studies. These cells are ideal for investigating APOM-dependent lipid signaling in lung cancer and barrier dysfunction. For detailed technical support, please contact Ascent Research.
