The ALG9 Knockout A-549 Polyclonal Cells consist of a heterogeneous population of A-549 human lung adenocarcinoma cells in which the ALG9 gene has been disrupted by CRISPR/Cas9. This polyclonal pool maintains the epithelial characteristics of the parental line while providing a diverse representation of ALG9 gene inactivation, avoiding the limitations of clonal selection. The cells are an ideal tool for studying N-glycosylation defects in a lung cancer context.
The A-549 cell line, established from the lung tumor tissue of a 58-year-old Caucasian male, is a widely used model for human lung adenocarcinoma. These cells display type II alveolar epithelial features and are extensively characterized for studies of cancer cell biology, drug responses, and respiratory cell signaling. Their well-documented molecular background and adherent growth facilitate reproducible experimental manipulation.
ALG9 is an alpha-1,2-mannosyltransferase that catalyzes mannose transfer to the lipid-linked oligosaccharide (LLO) precursor in the endoplasmic reticulum (ER), a step essential for N-glycan biosynthesis. It functions alongside ALG12 and depends on DPM1 for substrate supply. Disruption of ALG9 leads to incomplete LLO assembly, preventing the oligosaccharyltransferase (OST) complex from transferring glycans to nascent proteins. This results in misfolded protein accumulation and activation of the unfolded protein response (UPR) via sensors IRE1?? and PERK, which upregulate chaperones like GRP78/BiP and transcription factors XBP1 and ATF6. Consequently, the glycosylation and surface expression of downstream targets, including EGFR, integrins, and E-cadherin, are impaired, altering signaling and adhesion.
In A-549 cells, ALG9 knockout provides a powerful system to investigate glycosylation-dependent mechanisms in lung cancer. Aberrant glycosylation is a cancer hallmark, and loss of ALG9 specifically disrupts glycoproteins such as EGFR and integrins that drive proliferation and metastasis. This model also recapitulates features of ALG9-CDG, enabling dissection of ER stress and UPR pathways in epithelial pathology and offering a platform to identify glycosylation-related therapeutic targets.
Researchers can employ this polyclonal knockout model in diverse assays: Western blotting or lectin blotting to monitor glycoprotein changes, RT-qPCR to quantify UPR markers including XBP1 splicing and CHOP, and immunofluorescence to visualize ER stress proteins like GRP78/BiP. Flow cytometry can analyze cell surface glycosylation status, while viability assays under ER stress and migration/invasion tests assess functional consequences. RNA-seq enables global transcriptional profiling. For further information, please contact Ascent Research.
