The CD46 Knockout NCI-H1975 Polyclonal Cells are a CRISPR/Cas9-edited polyclonal knockout cell population generated by disrupting the CD46 gene in the human NCI-H1975 lung adenocarcinoma cell line. This heterogeneous pool of gene-edited cells provides a loss-of-function model for interrogating the biological functions of CD46 without isolating a single clone, preserving cellular diversity within the knockout context.
The NCI-H1975 cell line is an epithelial model derived from the pleural effusion of a non-smoking female patient with lung adenocarcinoma. It carries EGFR L858R and T790M mutations, which are associated with acquired resistance to first- and second-generation EGFR tyrosine kinase inhibitors (TKIs). This line is extensively used as an in vitro system for studying EGFR-mutant non-small cell lung cancer (NSCLC) and mechanisms underlying TKI resistance.
CD46 (membrane cofactor protein) is a complement regulatory protein that binds the opsonins C3b and C4b and serves as a cofactor for complement factor I?Cmediated proteolytic cleavage, thereby protecting host cells from complement attack. CD46 also acts as a receptor for measles virus hemagglutinin, adenovirus fiber knob, and bacterial Opa proteins from Neisseria species. Ligand binding triggers intracellular signaling cascades involving Src kinases, which phosphorylate and activate downstream effectors including Rac1 and NF-??B. CD46-dependent signaling also intersects with the autophagy pathway by regulating LC3 lipidation and the Beclin-1?CATG5 complex. In immune cells, CD46-mediated signaling promotes T cell co-stimulation through the adaptor SLP-76 and the guanine nucleotide exchange factor Vav. Its expression is induced by pro-inflammatory cytokines such as IFN-??, TNF-??, and IL-4 via STAT1 transcription factor activation.
In the NCI-H1975 TKI-resistant lung adenocarcinoma background, disruption of CD46 expression enables dissection of its roles in complement resistance, immune evasion, and autophagy-dependent survival mechanisms that may contribute to drug resistance. Loss of CD46-mediated complement inhibition could sensitize lung cancer cells to complement-dependent cytotoxicity, while altered autophagy regulation via the Src?CLC3?CBeclin-1 axis might influence cellular responses to TKI stress. This model is particularly relevant for exploring the interplay between complement regulatory proteins and autophagic flux in EGFR-mutant NSCLC with acquired TKI resistance.
Research applications include complement-mediated lysis assays to evaluate complement susceptibility, viral infection assays using measles or adenovirus to study entry mechanisms, fluorescence microscopy for LC3 puncta, western blotting for autophagy markers, transwell migration assays to assess cell motility, and cell viability assays under therapeutic stress. These polyclonal knockout cells are valuable tools for investigating CD46 in cancer immune evasion, pathogen entry, and autophagy-mediated tumorigenesis. For technical inquiries, please contact Ascent Research.
